This invention relates to optical local area networks, and more particularly to a low cost active node design.
Over the last several years, a number of local area network architectures have evolved to support data communications for a large user population. With the recent emergence of the personal computer, network control cards have been developed to permit these computers to be used as intelligent work stations for local area network applications. Most of these local area network cards employ coaxial cable as the transmission medium. This transmission medium has been used in both the baseband and broadband modes. With the rapid emergence of fiber optic technology, optical fiber has been examined as an alternative to coaxial cable in a number of local area network designs. Recently, several fiber optic components have been developed that can dramatically reduce the cost of integrating this technology into local area network designs.
In U.S. Ser. No. 777,934, filed Sept. 19, 1985, there is disclosed and claimed an active star network node design employing passive optical stars. The teachings of U.S. Ser. No. 777,934 are incorporated herein by reference. Although active star nodes employing optical stars can accommodate high data rate protocols such as Ethernet, these nodes are quite expensive. In addition, the nodes employing passive optical stars are heavy and relatively bulky. Furthermore, the optical star elements suffer splitter losses which degrade system performance.
It is therefore an object of the present invention to provide an optical node which is a fraction of the weight and size of known nodes and having a component cost about one-fifth the known design.
Yet another object of the invention is a low cost node that eliminates the splitter losses associated with nodes employing optical star elements.